Polymorphonuclear leukocytes (PMNs) play a major role in host defense against bacterial infections. PMNs are constantly passing from the gingival tissue, through the gingival crevice and out into the oral cavity. These PMNs are thought to play a host protective role in the gingival pulp areas. Recent evidence has focused attention on the modulating effects of heavy metals on the immune system and to a limited degree on the phagocytic systems. The oral tissues are a likely site for "higher-than-normal" concentrations of metal cations due to corrosion products of dental restorations and/or environmental contamination. Metals may have either a localized effect or systemic effect on human PMN activities, both protective and harmful. The question arises, could metal compounds either systemically or locally be modulating PMN functional capacity in oral tissue? Consequently, the objective of this proposal is to examine the effects of heavy metals such as chromium, mercury, gold, zinc, cobalt, lead, and cadmium on PMN functions in vitro. PMN functions to be tested are phagocytosis, superoxide generation, lysosome release and iodination by MPO/H2O2/ halide system. The metals in the form of salts (chlorides initially) will be tested at several concentrations 10 to the -3M and less) and any effects on PMN functions will be compared toleukotoxicity of the test compound. Information gained in these studies will serve as backgound data from which a more extensive study of this question can be formulated. In addition, the data will shed light on the potential in vivo effects of heavy metal accumulation in tissues and cells and lead to a more rational approach to understanding the consequences of exposure of the body to metals and possibly to the treatment of PMN-mediated inflammatory tissue destruction such as rheumatoid arthritis and chronic periodontitis.